Inpernal function: construct design matrix without the intercept term.
make_design_mat(lp, dat, remove_intercept = TRUE)Formula for the linear predictor part, as a string.
Data to construct the design matrix from.
Whether the first column should be removed. Default
is TRUE (to remove the intercept term).
Returns a list containing the constructed design matrix and the
original variable names. In the column names of the design matrix returned
, any : in variable names are replaced with . to avoid
computational issues when using the design matrix to fit model.